UPTON, NY-In chemical reactions, left and right can make a big difference. A "left-handed" molecule of a particular chemical composition could be an effective drug, while its mirror-image "right-handed" counterpart could be completely inactive. That's because, in biology, "left" and "right" molecular designs are crucial: Living organisms are made only from left-handed amino acids. So telling the two apart is important-but difficult.
Now, a team of scientists at the U.S. Department of Energy's Brookhaven National Laboratory and Ohio University has developed a new, simpler way to discern molecular handedness, known as chirality. They used gold-and-silver cubic nanoparticles to amplify the difference in left- and right-handed molecules' response to a particular kind of light. The study, described in the journal Nano Letters, provides the basis for a new way to probe the effects of handedness in molecular interactions with unprecedented sensitivity.
"Our discovery and methods based on this research could be extremely useful for the characterization of biomolecular interactions with drugs, probing protein folding, and in other applications where stereometric properties are important," said Oleg Gang, a researcher at Brookhaven's Center for Functional Nanomaterials and lead author on the paper. "We could use this same approach to monitor conformational changes in biomolecules under varying environmental conditions, such as temperature-and also to fabricate nano-objects that exhibit a chiral response to light, which could then be used as new kinds of nanoscale sensors."
The scientists knew that left- and right-handed chiral molecules would interact differently with "circularly polarized" light-where the direction of the electrical field rotates around the axis of the beam. This idea is similar to the way polarized sunglasses filter out reflected glare unlike ordinary lenses.
Other scientists have detected this difference, cal
|Contact: Karen McNulty Walsh|
DOE/Brookhaven National Laboratory